There has been known a cleaning method of sequentially dipping multiple wafers (hereinafter, referred to as a wafer set) as target objects in a chemical liquid reservoir storing a chemical liquid or a rinsing liquid reservoir storing a rinsing liquid, thereby removing contaminants adhered to respective wafers. Also, in order to sequentially dip the wafer set in the chemical liquid reservoir or the rinsing liquid reservoir, a carrying device is used. Also, as disclosed in Japanese Laid-Open Patent Publication No. 2002-118086, such a carrying device functions as a common handling unit for sequentially handling the wafer set.
In sequentially processing multiple wafer sets, when one wafer set uses the carrying device (the common handling unit), another wafer set cannot be carried by the carrying device (the common handling unit). Thus, a recipe is required to be adjusted in such a manner that while one wafer set does not use the carrying device, another wafer set can use the carrying device. However, depending on the content of the recipe, the time for allowing another wafer set to use the carrying device cannot be secured. As a result, the recipe for another wafer set is required to be largely delayed.